In the operation of bulk material belt conveyors, a scraper assembly is provided for removing adhering material from the load surface of a conveyor belt and depositing it into a discharge area. In the absence of a cleaning device, or as a result of a poorly functioning belt scraper, carry-over will be accumulated beneath the conveyor belt. In addition to constituting a nuisance, a large amount of valuable product will be deposited beneath the conveyor and may build-up sufficiently to interfere with operation of the conveyor. For example, a volume of spillage material 1/16" (1.6mm) deep and 1" (25mm) wide will produce approximately 21/2 cubic feet (0.075 cubic meters) of carry-over per 100 feet per minute (0.48 meters per second) of belt speed each hour. At a conveyor speed of 500 feet per minute (2.5 meters per second), this small stream produces approximately 10 tonnes of carry-over spillage every eight hours, based on a density of 100 lbs per cubic foot (1500 kg/cubic meter). Consequently, there is considerable interest in improving the operation and efficiency of conveyor belt cleaning devices.